The Claw Monkeys can be seen on the gold chase mission on Stranded 2 that appear as soon as you dig up 1 of the three gold bags.
There are 3 of those monkeys and are not very hard to defeat if prepared, be sure to bring some powerful weapons, like claw spears, and bows to attack them while running backwards.
You can also see them On the Pirate's island.
Even though they are seen in many places, you are more likely to spot them in Tesco Direct stores in Southern England. Some Wal-Mart stores have also reported several sightings around the United States.